The project aims to contribute to understanding of the biochemistry of insects, with especial emphasis on hormone action in development and metabolic regulation. In the forthcoming project period, we plan to concentrate on the insect fat body, using silkmoths as the chief animal material, and other species where appropriate. Both intact fat body and cell suspensions will be used. The synthesis and metabolism of specific proteins will be studied, including the mechanism of action of juvenile hormone in inducing yolk protein synthesis and the cell physiology of storage proteins. Studies on the uptake and release of trehalose and other sugars by fat body cells will be continued, as well as the regulation of carbohydrate metabolism in this tissue, as influenced by development, hormones, and experimental injury. The roles of cyclic nucleotides in biochemical regulation will be studied, in relation to hormone action, carbohydrate metabolism, and other processes.